Ok, this one is a bit cheesy, but very cool. The Mister Guy has released his beta app that uses the rear facing camera on your device, motion and touch to control your on screen mouse pointer. The application is only confirmed working on Android OS versions 2.2.2 and newer.
I personally have no use for such an application, but it is still a really cool idea. It would be a great back up plan if your current mouse breaks and you are in a pinch.
Summary and Downloads:
Application: Mr Mouse (Beta)
Developer:Â The Mister Guy
Cost:Â FREE